Magnetic Racetrack Memory is a non-volatile memory technology in which data is stored as magnetic domains along a thin strip or pillar of magnetic material, e.g., ferromagnetic material. This strip or pillar is referred to as the racetrack or track and typically is of dimensions on the order of approximately h=20 nm, 1=3 μm, w=90 nm (e.g., in a 90 nm technology). Each domain is created by a magnetic field resulting from current in a wire in close proximity to a portion of the track. Current passing along the length of the track causes the domains to move along the length of the track by the mechanism of spin momentum transfer. The state of a particular domain is determined by moving the domain to a position along the track where its magnetic polarity may be sensed by a Magnetic Tunnel Junction (MTJ) in close proximity to that position. The resistance of an MTJ changes based upon applied magnetic field. For this reason, an MTJ can be used as a magnetic field sensor.
Currently, there exists no memory technology that incorporates such Magnetic Racetrack Memory in a form providing a high density memory.
It would be highly desirable to provide a high density memory technology including an array of Magnetic Racetracks and a method to operate that array so as to provide a high density memory technology.